The invention relates to a method of carrying out, in a conduit, measurements on a fluid medium flowingxe2x80x94in particular in a pulsating currentxe2x80x94through said conduit, the conduit comprising a measuring region in which at least one parameter of the medium is determined during the measurement.
In a known method, measured values of the relevant parameter are continuously collected. Especially when the fluid does not move through the conduit in a continuous flow, it is possible that certain parameter values are not representative. For the purpose of separating non-usable measured values from usable measured values, various filter techniques are applied. It has been found that filtering these measurement data is time-consuming and does not always produce the desired effect.
Therefore, a need exists to obviate the above-mentioned drawback or to minimize same.
In accordance with the invention, this is achieved in defining an optimal window for measuring the parameter involved whereby the data provided from the measuring window are recorded or used for a further process or both. In this manner only the usable measurement data, i.e., those measurement data having a high reliability, are recorded or used or both as a parameter in a further process.
According to an inventive feature, for the purpose of defining the measuring window, determinations are made as to when a first pulse flow has passed the measuring region and when a next pulse flow will enter the measuring region. The method has the advantage that, during measuring, the measuring region is not affected by the flowing medium. In a preferred embodiment of the invention, the measuring window is defined by the moment when, just before a new pulse flow enters the measuring region, the momentary measurement data of the relevant parameter are recorded or supplied, or both, as a control signal for a further process. The latter method has the advantage that at the moment of measuring, the medium in the measuring region has had its longest period of rest. In the case that the medium is, for example, constituted by milk which is obtained by means of a milking installation, air bubbles that enter the milk during milking have the opportunity to escape from the milk, so that measurement is not affected by these air bubbles.
In accordance with another method of the invention, it is also possible to define the measuring window at the moment when the largest possible amount of the medium is present in the measuring region. By the largest possible amount of the medium is meant that the volume of the medium is largest in the measuring region. According to a further inventive feature, the measuring window is defined by determination of the conductivity of the medium. By means of a conductivity measurement it is possible to ascertain whether the medium is present in a certain region of the line and it is also possible to determine the volume of the medium in said region. Besides a conductivity measurement, according to another inventive feature, the measuring window can also be defined by optical or acoustic detection. This method of detecting the medium is especially suitable when the medium flows through the conduit in a pulsating current. In the case that a medium flows through the line in a pulsating current, according to the invention, it is also possible to define the measuring window on the basis of signals that are supplied by means which generate the pulsating current. Such a signal comprises in particular the frequency of the pulsating current.
The invention also relates to a device for carrying out measurements on a flowing medium, in particular a medium which is flowing in a pulsating current, as described above. According to an inventive feature, first measuring means are disposed in the conduit of said device for determining the flowing medium as well as second measuring means with the aid of which at least one parameter of the medium is determined. According to again another aspect of the invention, the first measuring means comprises an optical or an acoustic or a conductivity sensor, or any combination thereof. According to a further inventive feature, it is possible that the first measuring means is constituted by a device by means of which the pulsating current of the medium is generated. In the case of a milk line system with a teat cup, the second measuring means is constituted by a pulsator.
According to a further aspect of the invention, the second measuring means comprise a color sensor by means of which the colors of the medium are determined. Thus, in the case of a milking installation, it is possible to ascertain with a high degree of reliability whether the milk contains impurities, such as, for example, blood or pus. According to a further embodiment of the invention, the measuring region is situated in a bypass of the line through which the medium flows. Thereby the bypass is connected to the main line in such a manner that the medium comes to a rest more or less in the bypass. According to another inventive feature, the diameter of the bypass is smaller than that of the line through which the medium flows. According to a further aspect of the invention, in or near the bypass an air inlet means is disposed with the aid of which air or another gas, or both, is permitted to enter or injected into the bypass, or both, processes are involved. In this manner replacement of the medium in the bypass is stimulated.
According to an inventive feature, the first and second measuring means are disposed in a milk line system or in a teat cup.